You can turn a key in the ignition (I think it's) twice before you start the engine. So you turn the key once, it'll turn on your lights and hazards and various other things. Turn it again, and it'll switch on windows and air con and other such things. Turn it again and it'll start the car.

Turning it half way, so the lights are on on the dashboard, will turn the ignition on. Don't turn it as far as to start the engine.

Different cars have a different number of positions on the ignition switch, you'll need to work out which one you need to go to, but if it is in the position it would be in when the cars engine is running (after you've started it) the brake lights should work.

On almost all cars, they are wired so that the brake lights only work when you have the key turned in the ignition. If you just press the brake pedal without the ignition being turned on, the brake lights won't work. Same goes for headlights, indicators etc, most cars have headlights which turn off automatically when you turn the ignition off.

There isn't a "half way" as such.
Most modern ignition switches have a four position switch.

0 - or off
1 - accessory circuit becomes live - i.e radio etc
2 - LT ignition circuit goes live. The coil is on and energised. You should never leave the ignition switch in this position for longer than 30 secconds if the engine is off. You risk burning out your coil if you do so.
3 - Starter motor

(Original post by JC.)
You should never leave the ignition switch in this position for longer than 30 secconds if the engine is off. You risk burning out your coil if you do so.

i always knew there was a reason for not doing that, at college my mate used to leave his ignition on during lunch (eating in the cars!) and i kept telling him not to but didnt know what to say when he asked why!